Flowserve Seal Support Reservoir User Manual

Experience In Motion
Seal Support Reservoir
Flowserve seal support system for dual unpressurized and dual pressurized operation
Installation
Instructions
Introduction
This manual covers the installation and operation of Flowserve Seal Support Systems for dual unpressurized (API Plan 52/ANSI Plan 7352) and dual pressurized seals (API Plan 53A, 53B, 53C/ANSI Plan 7353). The following instructions describe the appropriate system, buffer/barrier uids, installation, start-up and maintenance.
Reservoir
The standard supply tank is designed in accordance with ASME Code Section VIII, Division 1. All tanks are welded in accordance with ASME Code Section IX. Tanks
include inlet, outlet, vent and ll, along with mounting lugs as minimum connection.
Sealing System Description
Supply tank assemblies can be used as reservoirs for dual seal designs. The
sealing system produced is dened as being either a thermal convection system
or a forced circulation system.
Support System Descriptions
API Plan 53A, 53B, 53C/ANSI Plan 7353A for dual pressurized seals
An API Plan 53A/ANSI 7353A is a pressurized dual seal system which is used in services where no process leakage to atmosphere is tolerated. The system
consists of dual mechanical seals with a barrier uid between them. The barrier uid in the supply tank is pressurized to a higher pressure than the seal chamber,
normally 15 to 25 psig (1 to 1.7 bar). Primary (inboard) seal leakage will be barrier
uid into the product. A small amount of leakage is customary.
An API Plan 53A/ANSI Plan 7353A is usually chosen over an API Plan 52/ ANSI Plan 7352 for dirty, abrasive or polymerizing products which would either damage
the seal faces or cause problems with the barrier uid system if an API Plan 52/
ANSI Plan 7352 is used. There are two disadvantages to an API Plan 53A/ANSI Plan 7353A which must be considered. First, there will always be some leakage
of barrier uid into the product. Normally, this leakage will be minute, and the
leakage rate can be monitored via the level gauges or other instrumentation. However, the product must be able to accommodate a small amount of contami-
nation from the barrier uid. Secondly, an API Plan 53A/ANSI Plan 7353A system
is dependent on having the supply tank pressure maintained at the proper level. If the supply tank pressure drops, seal leakage direction will be reversed and the
barrier uid will be contaminated with the process uid.
An Induced Circulation System is essentially the same as the thermal convec­tion system, except for the addition of a circulating device in the seal cavity which
provides for positive ow in the system. The addition of the circulating device provides for positive ow of barrier/buffer uid shown in Figure 1. Because supply
tanks provide for poor radiation and convection of heat to the atmosphere, it is common to add cooling coils inside the reservoir as a means of removing heat.
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Dual Inside Seal with Induced Circulation
Pressure source
4 feet (1.2 m)
maximum
1.5 - 2 feet
(0.45 -0.6 m)
minimum
Orifice option
Bypass line from pump discharge
Supply tank assembly
normally open
Level switch (low)
Pressure switch (low)
Pressure indicator
Cooling coils
Drain normally closed
Through Supply Tank with Cooling Coil Figure 1
Plan 53A/ANSI Plan 7353A
What
Pressurized barrier uid circulation
through reservoir.
Fluid is circulated by a pumping ring in the dual seal assembly
Why
Isolate process uid
Zero process emissions
Typically used <150 psig (10.3 bar) pressure
Plan 53B/ANSI Plan 7353B
What
Pressurized barrier uid circulation
with bladder accumulator.
Fluid is circulated by a pumping ring in the dual seal assembly.
Why
Isolate process uid.
Zero process emissions.
Higher pressure than Plan 53A.
Plan 53C/ANSI Plan 7353C
What
Pressurized barrier uid circulation with
piston accumulator.
Fluid is circulated by a pumping ring in the dual seal assembly.
Why
Isolate process uid.
Zero process emissions.
Higher pressure than Plan 53A.
Dynamic tracking of system pressure.
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